U.S. patent application number 13/007677 was filed with the patent office on 2011-11-03 for led package.
This patent application is currently assigned to ADVANCED OPTOELECTRONIC TECHNOLOGY, INC.. Invention is credited to MIN-TSUN HSIEH, CHI-WEI LIAO, CHIH-YUNG LIN, WEN-LIANG TSENG, CHING-LIEN YEH.
Application Number | 20110266574 13/007677 |
Document ID | / |
Family ID | 44857570 |
Filed Date | 2011-11-03 |
United States Patent
Application |
20110266574 |
Kind Code |
A1 |
LIAO; CHI-WEI ; et
al. |
November 3, 2011 |
LED PACKAGE
Abstract
An LED package includes a substrate, an LED die, and an
encapsulating layer. The LED die is arranged on the substrate. The
encapsulating layer covers the LED die and at least a part of the
substrate. The encapsulating layer includes a light dispersing
element. A light scattering intensity of the light dispersing
element is proportional to the light intensity of light generated
by the LED die and illuminated at the encapsulating layer. A
luminance at a center of the LED package is substantially identical
to that at a circumference of the LED package.
Inventors: |
LIAO; CHI-WEI; (Hsinchu,
TW) ; TSENG; WEN-LIANG; (Hsinchu, TW) ; LIN;
CHIH-YUNG; (Hsinchu, TW) ; HSIEH; MIN-TSUN;
(Hsinchu, TW) ; YEH; CHING-LIEN; (Hsinchu,
TW) |
Assignee: |
ADVANCED OPTOELECTRONIC TECHNOLOGY,
INC.
Hsinchu Hsien
TW
|
Family ID: |
44857570 |
Appl. No.: |
13/007677 |
Filed: |
January 17, 2011 |
Current U.S.
Class: |
257/98 ;
257/E33.059; 257/E33.074 |
Current CPC
Class: |
H01L 33/507 20130101;
H01L 2224/48091 20130101; H01L 2224/48091 20130101; H01L 2924/00014
20130101; H01L 33/508 20130101; H01L 2933/0091 20130101 |
Class at
Publication: |
257/98 ;
257/E33.059; 257/E33.074 |
International
Class: |
H01L 33/54 20100101
H01L033/54 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 29, 2010 |
CN |
201010159829.8 |
Claims
1. An LED package comprising: a substrate; an LED die arranged on
the substrate; and an encapsulating layer covering the LED die,
wherein the encapsulating layer further comprises a light
dispersing element with a light scattering intensity in
proportional to a light intensity of light generated by the LED die
and illuminated on the encapsulating layer.
2. The LED package of claim 1, wherein the light dispersing element
is an atomization layer or a sandblasting layer on an surface of
the encapsulating layer.
3. The LED package of claim 2, wherein a density of atomization of
the atomization layer or micro-recesses of the sandblasting layer
decreases from a center to a periphery of the encapsulating
layer.
4. The LED package of claim 1, wherein the light dispersing element
includes light scattering particles in the encapsulating layer.
5. The LED package of claim 4, wherein a density of the light
scattering particles decreases from a center to a periphery of the
encapsulating layer.
6. The LED package of claim 1, wherein the encapsulating layer
includes luminescent material with a space between the luminescent
material and the LED die.
7. The LED package of claim 6, wherein the luminescent material is
at an outer surface, an inner surface, or an inside of the
encapsulating layer.
8. The LED package of claim 6, wherein the luminescent material is
garnet compound, silicate, sulfide, phosphate, nitride, oxynitride,
or SiAlON.
9. The LED package of claim 1, wherein a density of the luminescent
material is proportional to the light intensity of light generated
by the LED die and illuminated on the encapsulating layer.
10. The LED package of claim 9, wherein the density of the
luminescent material decrease from a center to a periphery of the
encapsulating layer.
11. An LED package comprising: a substrate; an LED die arranged on
the substrate; and an encapsulating layer with luminescent material
covering the LED die, wherein the encapsulating layer further
comprises a light dispersing element with a light scattering
intensity and luminescent material density in proportional to a
light intensity of light generated by the LED die and illuminated
on the encapsulating layer.
12. The LED package of claim 11, wherein the encapsulating layer
has a configuration of a hollow hemisphere.
13. The LED package of claim 11, wherein the encapsulating layer
has a configuration of a solid hemisphere.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present disclosure generally relates to LED technology,
and particularly to an LED package.
[0003] 2. Description of the Related Art
[0004] Light emitting diodes (LEDs) have been promoted as a widely
used light source by many advantages, such as high luminosity, low
operational voltages, low power consumption, compatibility with
integrated circuits, easy driving, long-term reliability, and
environmental friendliness. LEDs are commonly applied in a
plurality of lighting applications.
[0005] However, LED packages must overcome certain light
illumination uniformity challenges. LED is a point light source and
the center of the commonly used LED package has higher light
intensity than the circumference. The non-uniformity of light
illumination of the LED package will cause bad effects on the usage
of LED.
[0006] What is needed, therefore, is an LED package, which can
increase light illumination uniformity, and ameliorate the
described limitations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Many aspects of the disclosure can be better understood with
reference to the drawings. The components in the drawings are not
necessarily drawn to scale, the emphasis instead being placed upon
clearly illustrating the principles of the LED package. Moreover,
in the drawings, like reference numerals designate corresponding
parts throughout the views.
[0008] FIG. 1 is a schematic cross section of an LED package in
accordance with a first embodiment.
[0009] FIG. 2 is a schematic plot of distribution curve of luminous
intensity of the LED package of FIG. 1.
[0010] FIG. 3 is a view similar to FIG. 1 showing the LED package
of FIG. 1 having a modified substrate.
[0011] FIG. 4 is a schematic cross section of an LED package in
accordance with a second embodiment.
[0012] FIG. 5 is a schematic cross section of an LED package in
accordance with a third embodiment.
[0013] FIG. 6 is a schematic top view of the atomization level of
the outer surface of the LED package of FIG. 5.
[0014] FIG. 7 is a schematic cross section of an LED package in
accordance with a fourth embodiment.
[0015] FIG. 8 is a schematic cross section of an LED package in
accordance with a fifth embodiment.
[0016] FIG. 9 is a schematic cross section of an LED package in
accordance with a sixth embodiment.
[0017] FIG. 10 is a schematic cross section of an LED package in
accordance with a seventh embodiment.
[0018] FIG. 11 is a schematic cross section of an LED package in
accordance with an eighth embodiment.
DETAILED DESCRIPTION
[0019] Embodiments of an LED package as disclosed are described in
detail here with reference to the drawings.
[0020] Referring to FIG. 1, an LED package 50 in accordance with a
first embodiment includes a substrate 51, an LED die 52 arranged on
the substrate 51, an encapsulating layer 53 covering the LED die
52, and a light dispersing element inside the encapsulating layer
53. The encapsulating layer 53 includes a luminescent material 55.
The density of the light dispersing element is proportional to the
intensity of light illuminated on the encapsulating layer 53.
[0021] The substrate 51 is Al.sub.2O.sub.3, silicon, SiC, ceramic,
polymer, or insulant quartz. The substrate 51 includes a circuit
electrically connecting with the LED die 52. The circuit includes a
first electrode 510 and a second electrode 512. The LED die 52 is
arranged on the first electrode 510 and electrically connecting
with the first electrode 510 and the second electrode 512 through
wires 514. The LED die 52 can also be arranged by manner of
flip-chip (not shown). The first electrode 510 and the second
electrode 512 of the circuit extend from the upper surface to the
bottom surface of the substrate 51 to make the LED package 50 a
surface mounted device (SMD).
[0022] The LED die 52 can be a compound semiconductor of group
III-V elements or group II-VI elements. Light emitted from the LED
die 24 can be visible, invisible, or a mixture of visible and
invisible.
[0023] The encapsulating layer 53 is a transparent hemispherical
shell with uniform thickness covering the LED die 52.
Understandably, a number of the LED die 52 can be more than one and
the encapsulating layer 53 can cover a plurality of LED dies. The
encapsulating layer 53 defines a space 54 with the substrate 51,
and the LED die 52 is arranged inside the space 54. The
encapsulating layer 53 can be transparent material, such as
silicone, epoxy, quartz, or glass.
[0024] The light dispersing element is a plurality of light
scattering particles 56 spreading in the encapsulating layer 53.
The density of the light scattering particles 56 is proportional to
the intensity of light illuminated on the encapsulating layer 53
from the LED die 52. In this embodiment, the intensity of light
illuminated on the encapsulating layer 53 from the LED die 52 is
higher at the top (center) and lower at the bottom (periphery) of
the encapsulating layer 53. So that the density of the light
scattering particles 56 is higher at the top (center) and lower at
the bottom (periphery) of the encapsulating layer 53. The light
scattering particles 56 can be TiO.sub.2, plastic,
polymethylmethacrylate (PMMA), fused silica, Al.sub.2O.sub.3, MgO,
or other transparent oxide. The shape of the light scattering
particles 56 are not limited and can be spherical, rod, or any
other shape. In this embodiment, the light scattering particles 56
are spherical.
[0025] The density of the luminescent material 55 is proportional
to the intensity of light illuminated on the encapsulating layer 53
from the LED die 52. In this embodiment, the density of the
luminescent material 55 is higher at the top (center) of the
encapsulating layer 53 and lower at the bottom (periphery) of the
encapsulating layer 53. Other optical element can also be filled
between the LED die 52 and the encapsulating layer 53. The
luminescent material 55 can be garnet compound, silicate, sulfide,
phosphate, nitride, oxynitride, or SiAlON.
[0026] The LED package 50 includes an optical axis I. FIG. 2 is a
schematic plot of distribution curve of luminous intensity of the
LED package of FIG. 1. Referring to FIG. 2, the x-axis is the angle
away from the optical axis I, and the y-axis is the intensity of
light illuminated. The light intensity is basically the same near
the optical axis I which means that the light illuminated by the
LED package 50 has a higher uniformity.
[0027] The substrate 51 of the LED package 50 in accordance with
the first embodiment can be of other structure as shown in FIG. 3.
The substrate 51a includes a circuit electrically connecting to an
LED die 52a. The circuit includes a first electrode 510a and a
second electrode 512a. A heat dissipating lump 511a is arranged in
the middle of the substrate 51a. The LED die 52a is arranged on the
heat dissipating lump 511a and electrically connects with the first
electrode 510a and the second electrode 512a through wires 514a.
The first electrode 510a and the second electrode 512a of the
circuit extend from the upper surface to the bottom surface of the
substrate 51a to make the LED package 50a a surface mounted device
(SMD).
[0028] Referring to FIG. 4, an LED package in accordance with a
second embodiment includes an encapsulating layer 53b directly
covering the LED die 52b by molding. The luminescent material 55b
and the light scattering particles 56b are arranged inside the
encapsulating layer 53b.
[0029] Referring to FIG. 5, an LED package 40 in accordance with a
third embodiment includes a substrate 41, an LED die 42 arranged on
the substrate 41, an encapsulating layer 43 covering the LED die
42, and a luminescent material 45 inside the encapsulating layer
43. The difference from the first embodiment is that there is no
light scattering particles in the encapsulating layer 43 and the
outer surface of the encapsulating layer 43 includes an atomization
layer 46 as light dispersing element by atomization treatment. The
degree of atomization is proportional to the light intensity
illuminated on the encapsulating layer 43 from the LED die 42. In
this embodiment, the degree of atomization is higher at the center
and lower at the periphery. (as shown in FIG. 6)
[0030] Referring to FIG. 7, an LED package 70 in accordance with a
fourth embodiment includes a substrate 71, an LED die 72 arranged
on the substrate 71, an encapsulating layer 73 covering the LED die
72, and a luminescent material 75 inside the encapsulating layer
73. The difference from the first embodiment is that there is no
light scattering particles in the encapsulating layer 73 and the
outer surface of the encapsulating layer 73 includes a sandblasted
layer 76 as light dispersing element by sandblasting. The sand
blasting layer 76 is formed by high speed impact of copper ore
sand, quartz sand, emery sand, iron sand, or sea sand to the outer
surface of the encapsulating layer 73. The sand blasting layer 76
includes a plurality of micro-recesses (not labeled) therein. The
density of the micro-recesses of the sandblasted layer 76 is
proportional to the light intensity illuminated on the
encapsulating layer 73 from the LED die 72. In this embodiment, the
density of micro-recesses of the sandblasted layer 76 is higher at
the center and lower at the periphery.
[0031] Referring to FIG. 8, an LED package 20 in accordance with a
fifth embodiment includes a substrate 21, an LED die 22 arranged on
the substrate 21, and an encapsulating layer 23 covering the LED
die 22. There is a space 24 defined between the substrate 21 and
the encapsulating layer 23. The difference from the first
embodiment is that a layer of luminescent material 25 is arranged
on the inner surface of the encapsulating layer 23, and there is no
luminescent material in the encapsulating layer 23. The layer of
luminescent material 25 is spaced from the LED die 22 with a
certain distance to prevent the layer of luminescent material 25
from high temperature. A plurality of light scattering particles 26
is arranged inside the encapsulating layer 23. The density of the
plurality of light scattering particles 26 is proportional to the
light intensity illuminated on the encapsulating layer 23 from the
LED die 22. In this embodiment, the intensity of light illuminated
on the encapsulating layer 23 from the Led die 22, and,
correspondingly, densities of the light scattering particles 26 are
higher at the center and lower at the bottom. The light scattering
particles 26 can be TiO.sub.2, plastic, polymethylmethacrylate
(PMMA), fused silica, Al.sub.2O.sub.3, MgO, or other transparent
oxide. The shape of the light scattering particles 26 is not
limited and can be spherical, longitudinal, or other shape. In this
embodiment, the light scattering particles 26 are spherical.
[0032] FIG. 9 shows an LED package 60 in accordance with a sixth
embodiment including a layer of luminescent material 65 arranged on
the inner surface of the encapsulating layer 63. The difference
from the fifth embodiment is that an atomization layer 66 is
arranged on the outer surface of the encapsulating layer 63 without
any light scattering particles inside the encapsulating layer
63.
[0033] FIG. 10 shows an LED package 80 in accordance with a seventh
embodiment including a layer of luminescent material 85 arranged on
the inner surface of an encapsulating layer 83. The difference from
the sixth embodiment is that a sandblasted layer 86 is arranged on
the outer surface of the encapsulating layer 83 to replace the
atomization layer 66 of the sixth embodiment.
[0034] FIG. 11 shows an LED package 30 in accordance with an eighth
embodiment including an LED die 32, an encapsulating layer 33, and
a plurality of light scattering particles 36 inside the
encapsulating layer 33. This embodiment is similar to the fifth
embodiment of FIG. 8 except that a layer of luminescent material 35
is arranged on the outer surface of the encapsulating layer 33. The
density of the luminescent material in the layer of luminescent
material 35 is proportional to the light intensity illuminated on
the encapsulating layer 33 from the LED die 32. The densities of
the light scattering particles 36 are proportional to the light
intensity illuminated on the encapsulating layer 33 from the LED
die 32. The layer of luminescent material 35 can be arranged on the
inner surface, the outer surface, or both the two surfaces of the
encapsulating layer 33 to increase the uniformity of light emitted
out from the LED die 32. The outer surface of the layer of
luminescent material 35 can include an atomization layer or a
sandblasted layer or both.
[0035] It is to be understood, however, that even though numerous
characteristics and advantages of the disclosure have been set
forth in the foregoing description, together with details of the
structures and functions of the embodiment(s), the disclosure is
illustrative only, and changes may be made in detail, especially in
matters of shape, size, and arrangement of parts within the
principles of the disclosure to the full extent indicated by the
broad general meaning of the terms in which the appended claims are
expressed.
* * * * *